1. Field of the Invention
The present invention relates to fireplaces and, in particular, to direct vent gas fireplaces.
2. Description of the Related Art
Gas fireplaces of conventional design typically utilize a source of combustion air from the room being heated. This lowers the efficiency of the gas fireplace because a portion of the heated air in the room is drawn into the combustion chamber and exhausted up the chimney. It is known to provide separate ducting from the outside ambient environment to the combustion chamber to increase the efficiency of the fireplace. The ducted air provides a source of oxygen for combustion in the combustion chamber and decreases the amount of air from the room being heated which is exhausted up the chimney. Such ducting, however, requires additional materials and labor to install.
It is also known in the art to utilize concentric flue pipes to exhaust combustion products to the outside environment and supply combustion air from the outside environment. Such fireplaces are termed "direct vent" fireplaces and are disclosed, e.g., in U.S. Pat. Nos. 4,793,322 (Shimek et al.) and 4,909,227 (Rieger). A direct vent fireplace has the advantage of utilizing a common concentric flue pipe assembly to both exhaust combustion products from and supply combustion air to the combustion chamber. Moreover, only a single opening need be cut through an exterior wall of a house to accommodate the concentric flue pipe assembly.
In general, a direct vent fireplace has a first pipe with a diameter larger than and disposed concentrically around a second pipe. The duct formed by the second pipe is used to convey exhaust products from the combustion chamber to the outside environment. The annular space formed between the first and second pipes defines a fresh air conduit through which combustion air flows from the outside ambient environment into the combustion chamber.
A problem with direct vent gas fireplaces is that the concentric flue pipe assembly cannot be easily vented in both a horizontal or vertical direction. Shimek et al. and Rieger disclose direct vent fireplaces which respectively connect the concentric flue to the back wall and top wall of the fireplace. A concentric flue attached to the back wall of the fireplace may be easily extended through an adjacent side wall of the house. However, if it is desirable to exhaust the concentric flue in a vertical direction, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow. Thus, additional floor space is required to accommodate the projected footprint of the fireplace and concentric flue pipe assembly.
A concentric flue pipe assembly attached to the top of a direct vent fireplace has a similar problem when it is desired to vent the concentric flue in a horizontal direction (see, e.g., Rieger at Col. 1, lines 23-32). That is, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow.
Because of two possible installation configurations, i.e., vertical or horizontal venting of the concentric flue pipe assembly, it is necessary with conventional direct vent fireplace designs to provide two totally different configurations. That is, for relatively close placement of the fireplace adjacent the outside wall of the house, it is necessary to provide one configuration allowing attachment of the concentric flue pipe assembly to the back of the fireplace for horizontal venting, and a second configuration allowing attachment of the concentric flue pipe assembly to the top of the fireplace for vertical venting. The necessity to provide two different configurations increases inventory requirements at the factory. An installer must order either a vertical or horizontal venting fireplace prior to installation. What is needed, therefore, is a direct vent fireplace which reduces the required inventory which must be kept on hand.
Moreover, an installer may not know whether a vertical or horizontal venting fireplace is needed prior to installation. Therefore, what is needed in the art is a direct vent gas fireplace allowing a concentric flue to be selectively vented in either a horizontal or vertical direction.